The purpose of this program is to develop instrumentation and techniques for automated cytology of exfoliated urinary bladder epithelium, to be used in early detection and diagnosis of bladder carcinoma. Additional goals are the use this instrument system with specially developed cytochemical procedures for measuring conformational changes in DNA and RNA in situ to differentiate between cells of papillomas, low grade carcinomas and high grade carcinomas; and to quantitate irradiation and drug treatment effect by the same means. The instrument system consists of a flow-through cytofluorometer which can be used to measure native and denatured DNA and RNA per cell within intact cells in suspension. It will be modified to also measure optical parameters for differentiating cells by fluorescent pulse shape and by coherent light scatter. Multiparameter measurements per cell at a rate of several hundred per second will be obtained on 5,000 cells per sample, then stored and analyzed by a dedicated mini-computer to characterize different kinds of cell populations by pattern recognition techniques. Work to date has shown that this approach with metachromatic fluorescent staining by acridine orange will discriminate between bladder epithelial cells and other cell types, with some overlapping. We have now developed new cytochemical techniques for measuring conformational changes in DNA and RNA in situ that will distinguish cell types by qualitative as well as quantitative differences in DNA and RNA, with initially excellent results.